Fluorescent monomers and tagged treatment polymers containing same for use in industrial water systems

ABSTRACT

Fluorescent monomers are described and claimed which are synthesized by reacting a substituted or non-substituted naphthalic anhydride with an amine and with a moiety containing a polymerizable group. Such monomers are useful for the preparation of tagged treatment polymers. Such tagged treatment polymers are useful as scale inhibitors in industrial water systems.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation-in-part patent application ofU.S. patent application Ser. No. 09/560,881 FLUORESCENT MONOMERS ANDTAGGED TREATMENT POLYMERS CONTAINING SAME FOR USE IN INDUSTRIAL WATERSYSTEMS, filed Apr. 27, 2000, now U.S. Pat. No. 6,645,881.

FIELD OF THE INVENTION

This invention relates to fluorescent monomers. In another aspect, thisinvention relates to tagged treatment polymers that contain thesefluorescent monomers. In a further aspect, this invention relates to theuse of tagged treatment polymers containing fluorescent monomer(s)therein in industrial water systems.

BACKGROUND OF THE INVENTION

In many industrial water systems that employ polymers as water treatmentagents it may be desirable to tag or mark such polymers to facilitatemonitoring thereof. By the term “monitoring” is meant herein any type oftracing or tracking to determine the location or route of the polymers,and any type of determination of the concentration or amount of thepolymer at any given site, including singular or intermittent orcontinuous monitoring. For instance, it may be desirable to monitorwater treatment polymers in water systems, or to monitor polymers thatmay be present in waste fluids before disposal, or to monitor thepolymer used in fluids for down-hole oil well applications, or tomonitor polymers that may be present in fluids used to wash amanufactured product.

As seen from the above list of possible applications of polymermonitoring, the purpose of such monitoring may be to trace or track ordetermine the level of the polymer itself, or to trace or track ordetermine the level of some substance in association with the polymer,or to determine some property of the polymer or substance in associationwith the polymer, for instance its leachability.

There are many industrial water systems. Because water resources arebecoming limited and efficient utilization of water is required, variousmethods have been adopted to reduce the amount of water used in allindustrial water systems. As the methods for reducing the amount ofwater are put into practice, unfavorable events can occur. Theseunfavorable events occur because the quality of the water in the systemis progressively deteriorated. These unfavorable events can include theformation of scale.

To prevent or minimize unfavorable events, various kinds of treatmentagents for treatment of water systems have been used. It has been foundthat organic substances, including certain types of treatment polymers,are effective for preventing formation of scale. These certain types oftreatment polymers are known to persons of ordinary skill in the art ofindustrial water treatment and are widely used by themselves or as oneof many possible components in scale inhibition products.

When a treatment polymer is used for preventing formation of scale theconcentration of the treatment polymer in the water system is theimportant factor so that the treatment polymer performs the desiredfunction with good efficiency. For example, a treatment polymer added toa cooling water system can be consumed by many causes. With consumption,the amount of the treatment polymer dissolved in the cooling water doesnot remain the same as the amount added to the cooling water. Therefore,it is important for the optimum operation of an industrial water systemthat practical methods are known to determine the concentration oftreatment polymers in the water of the industrial water system.

In general practice, the amount of the treatment polymer added to thewater in an industrial water system can be measured using variousanalytical methods. The use of an inert fluorescent tracer or massbalance measurement method as described in U.S. Pat. Nos. 4,783,314;4,992,380; and 5,171,450, hereby incorporated by reference; to performthis analysis is known in the art.

In the inert fluorescent tracer method, an inert fluorescent tracer isadded to an industrial water system, with the amount of inertfluorescent tracer added being proportional to the amount of thetreatment polymer added. By using a fluorometer to measure thefluorescent signal of the inert fluorescent tracer, the amount of theinert fluorescent tracer can be determined by using a calibration curveto relate the amount of fluorescent signal detected to the amount of theinert fluorescent tracer present. Because the inert fluorescent tracerand the treatment polymer are added to the industrial water system inknown proportions, by knowing the amount of inert fluorescent tracerpresent it also means that the amount of treatment polymer present isknown.

The inert fluorescent tracer method can be conducted on-line and in realtime so that any changes in the amount of treatment polymer being addedto the system can be made immediately.

As a complement to the use of an inert tracer system, it has been foundthat treatment polymers that are used as components of scale inhibitorsin industrial water systems could be monitored if tagged with afluorescent monomer. The amount of fluorescent monomer incorporated intothe tagged treatment polymer must be enough so that the fluorescence ofthe tagged treatment polymer can be adequately measured; however, itmust not be so much that the performance of the tagged treatment polymeras a treatment agent for the water is decreased. Because theconcentration of the tagged treatment polymer itself can be determinedusing a fluorometer, it is now possible to measure consumption of thetagged treatment polymer directly. It is important to be able to measureconsumption directly because consumption of a treatment polymer usuallyindicates that a non-desired event, such as scaling, is occurring. Thus,by being able to measure consumption of the tagged treatment polymer,there can be achieved an on-line, real time, in-situ measurement ofscaling activity in the cooling system.

Certain tagged treatment polymers are known, see U.S. Pat. No.5,986,030, and U.S. patent application Ser. No. 09/465,146, filed Dec.16, 1999, now pending, hereby incorporated by reference. However, thereis not an abundance of viable tagged treatment polymers for use astreatment polymers in industrial water systems. Therefore, it isdesirable to produce additional tagged treatment polymers that have afluorescent signal so that a fluorometer can be used to measure thefluorescent signal of the tagged treatment polymer and determine theconcentration of tagged treatment polymer currently present in theindustrial water system from that information.

It is known that tagging of polymers is difficult to accomplish becauseof the difficulty in chemically combining fluorescent moieties withnon-fluorescent polymers. Therefore, in order to synthesize taggedtreatment polymers it is also desirable to produce fluorescent monomersthat are readily polymerized to form tagged treatment polymers.

SUMMARY OF THE INVENTION

The first aspect of the instant claimed invention is a fluorescentmonomer selected from the group consisting of compounds of the formulae:

-   -   wherein R₃ is sulfonic acid and its salts or carboxylic acid and        its salts or allyloxy or vinylbenzyloxy; and R₄ is sulfonic acid        and its salts or carboxylic acid and its salts or allyloxy or        vinylbenzyloxy; with the proviso that when one of R₃ or R₄ is        sulfonic acid and its salts or carboxylic acid and its salts,        the other must be allyloxy or vinylbenzyloxy.

The second aspect of the instant claimed invention is a tagged treatmentpolymer selected from the group consisting of:G_(a)Q_(j)W_(t)  (1)

-   -   wherein G is Monomer (Purple), as previously defined;    -   wherein Q is selected from the group consisting of acrylic acid        and salts thereof, methacrylic acid and salts thereof, maleic        acid and salts thereof, maleic anhydride, acrylamide, crotonic        acid, acrylamidomethylpropane sulfonic acid and salts thereof;    -   wherein W is selected from the group consisting of:        acrylic acid and salts thereof, methacrylic acid and salts        thereof, itaconic acid and salts thereof, maleic acid and salts        thereof, maleic anhydride, crotonic acid and salts thereof,        acrylamide, methacrylamide, vinyl sulfonic acid, styrene        sulfonate, N-tertbutylacrylamide, N-isopropylacrylamide,        butoxymethylacrylamide, N,N-dimethylacrylamide,        N,N-diethylacrylamide, dimethylaminoethyl acrylate methyl        chloride quaternary salts, dimethylaminoethyl acrylate benzyl        chloride quaternary salts, dimethylaminoethyl acrylate methyl        sulfate quaternary salt, dimethylaminoethyl methacrylate methyl        sulfate quaternary salt, dimethylaminoethyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl methacrylamide        methyl sulfate quaternary salts, diallyldimethyl ammonium        chloride, N-vinyl formamide, dimethylamino ethyl methacrylate        acid salts (including, but not limited to, sulfuric acid and        hydrochloride acid salts), dimethylaminoethyl methacrylate        methyl chloride quaternary salt, dimethylaminoethyl methacrylate        benzyl chloride quaternary salt, methacrylamidopropyl trimethyl        ammonium chloride, acrylamidopropyl trimethyl ammonium chloride,        methylene bis acrylamide, triallylamine, acid salts of        triallylamine, ethylene glycol dimethacrylate,        hydroxymethylacrylate, hydroxyethylacrylate,        hydroxypropylacrylate, hydroxypropylmethacrylate, diethylene        glycol dimethacrylate, triethylene glycol dimethylacrylate,        polyethylene glycol dimethacrylate, glycidyl methacrylate,        acrylamidomethylpropane sulfonic acid and the sodium salt        thereof, vinyl alcohol, vinyl acetate, and N-vinylpyrrolidone;

with the proviso that Q and W cannot both be the same;

-   -   wherein a is from about 0.001 to about 10.0 mole percent;    -   wherein j is from about 0 to about 99.999 mole percent;    -   wherein t is from about 0 to about 99.999 mole percent; and    -   wherein a+j+t=100;        G_(a)Q_(v)W_(f)S_(c)  (2)    -   wherein G is as previously defined;    -   wherein Q is as previously defined;    -   wherein W is as previously defined, with the proviso that Q and        W cannot both be the same;    -   wherein S is selected from the group consisting of        sulfomethylacrylamide and sulfoethylacrylamide;    -   wherein a is from about 0.001 to about 10.00 mole percent;    -   wherein v is from about 0 to about 97.999 mole percent;    -   wherein f is from about 1 to about 97.999 mole percent;    -   wherein c is from about 1 to about 40 mole percent; and    -   wherein a+v+f+c=100.

The third aspect of the instant claimed invention is a process for theinhibition of scale formation in an industrial water system whichcomprises introducing into said industrial water system a taggedtreatment polymer selected from the group consisting of:G_(a)Q_(j)W_(t)  (1)

-   -   wherein G is Monomer (Purple), as previously defined;    -   wherein Q is selected from the group consisting of acrylic acid        and salts thereof, methacrylic acid and salts thereof, maleic        acid and salts thereof, maleic anhydride, acrylamide, crotonic        acid, acrylamidomethylpropane sulfonic acid and salts thereof;    -   wherein W is selected from the group consisting of:        acrylic acid and salts thereof, methacrylic acid and salts        thereof, itaconic acid and salts thereof, maleic acid and salts        thereof, maleic anhydride, crotonic acid and salts thereof,        acrylamide, methacrylamide, vinyl sulfonic acid, styrene        sulfonate, N-tertbutylacrylamide, N-isopropylacrylamide,        butoxymethylacrylamide, N,N-dimethylacrylamide,        N,N-diethylacrylamide, dimethylaminoethyl acrylate methyl        chloride quaternary salts, dimethylaminoethyl acrylate benzyl        chloride quaternary salts, dimethylaminoethyl acrylate methyl        sulfate quaternary salt, dimethylaminoethyl methacrylate methyl        sulfate quaternary salt, dimethylaminoethyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl methacrylamide        methyl sulfate quaternary salts, diallyldimethyl ammonium        chloride, N-vinyl formamide, dimethylamino ethyl methacrylate        acid salts (including, but not limited to, sulfuric acid and        hydrochloride acid salts), dimethylaminoethyl methacrylate        methyl chloride quaternary salt, dimethylaminoethyl methacrylate        benzyl chloride quaternary salt, methacrylamidopropyl trimethyl        ammonium chloride, acrylamidopropyl trimethyl ammonium chloride,        methylene bis acrylamide, triallylamine, acid salts of        triallylamine, ethylene glycol dimethacrylate,        hydroxymethylacrylate, hydroxyethylacrylate,        hydroxypropylacrylate, hydroxypropylmethacrylate, diethylene        glycol dimethacrylate, triethylene glycol dimethylacrylate,        polyethylene glycol dimethacrylate, glycidyl methacrylate,        acrylamidomethylpropane sulfonic acid and the sodium salt        thereof, vinyl alcohol, vinyl acetate, and N-vinylpyrrolidone;

with the proviso that Q and W cannot both be the same;

-   -   wherein a is from about 0.001 to about 10.0 mole percent;    -   wherein j is from about 0 to about 99.999 mole percent;    -   wherein t is from about 0 to about 99.999 mole percent; and    -   wherein a+j+t=100;        G_(a)Q_(v)W_(f)S_(c)  (1)    -   wherein G is as previously defined;    -   wherein Q is as previously defined;    -   wherein W is as previously defined, with the proviso that Q and        W cannot both be the same;    -   wherein S is selected from the group consisting of        sulfomethylacrylamide and sulfoethylacrylamide;    -   wherein a is from about 0.001 to about 10.00 mole percent;    -   wherein v is from about 0 to about 97.999 mole percent;    -   wherein f is from about 1 to about 97.999 mole percent;    -   wherein c is from about 1 to about 40 mole percent; and    -   wherein a+v+f+c=100.        in an amount sufficient to inhibit scale formation.

The fourth aspect of the instant claimed invention is a method formaintaining the desired amount of tagged treatment polymer in anindustrial water system comprising the steps of:

i) adding to said industrial water system a tagged treatment polymer,selected from the group consisting of:G_(a)Q_(j)W_(t)  (1)

-   -   wherein G is Monomer (Purple), as previously defined;    -   wherein Q is selected from the group consisting of acrylic acid        and salts thereof, methacrylic acid and salts thereof, maleic        acid and salts thereof, maleic anhydride, acrylamide, crotonic        acid, acrylamidomethylpropane sulfonic acid and salts thereof;    -   wherein W is selected from the group consisting of:        acrylic acid and salts thereof, methacrylic acid and salts        thereof, itaconic acid and salts thereof, maleic acid and salts        thereof, maleic anhydride, crotonic acid and salts thereof,        acrylamide, methacrylamide, vinyl sulfonic acid, styrene        sulfonate, N-tertbutylacrylamide, N-isopropylacrylamide,        butoxymethylacrylamide, N,N-dimethylacrylamide,        N,N-diethylacrylamide, dimethylaminoethyl acrylate methyl        chloride quaternary salts, dimethylaminoethyl acrylate benzyl        chloride quaternary salts, dimethylaminoethyl acrylate methyl        sulfate quaternary salt, dimethylaminoethyl methacrylate methyl        sulfate quaternary salt, dimethylaminoethyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl methacrylamide        methyl sulfate quaternary salts, diallyldimethyl ammonium        chloride, N-vinyl formamide, dimethylamino ethyl methacrylate        acid salts (including, but not limited to, sulfuric acid and        hydrochloride acid salts), dimethylaminoethyl methacrylate        methyl chloride quaternary salt, dimethylaminoethyl methacrylate        benzyl chloride quaternary salt, methacrylamidopropyl trimethyl        ammonium chloride, acrylamidopropyl trimethyl ammonium chloride,        methylene bis acrylamide, triallylamine, acid salts of        triallylamine, ethylene glycol dimethacrylate,        hydroxymethylacrylate, hydroxyethylacrylate,        hydroxypropylacrylate, hydroxypropylmethacrylate, diethylene        glycol dimethacrylate, triethylene glycol dimethylacrylate,        polyethylene glycol dimethacrylate, glycidyl methacrylate,        acrylamidomethylpropane sulfonic acid and the sodium salt        thereof, vinyl alcohol, vinyl acetate, and N-vinylpyrrolidone;

with the proviso that Q and W cannot both be the same;

-   -   wherein a is from about 0.001 to about 10.0 mole percent;    -   wherein j is from about 0 to about 99.999 mole percent;    -   wherein t is from about 0 to about 99.999 mole percent; and    -   wherein a+j+t=100;        G_(a)Q_(v)W_(f)S_(c)  (2)    -   wherein G is as previously defined;    -   wherein Q is as previously defined;    -   wherein W is as previously defined, with the proviso that Q and        W cannot both be the same;    -   wherein S is selected from the group consisting of        sulfomethylacrylamide and sulfoethylacrylamide;    -   wherein a is from about 0.001 to about 10.00 mole percent;    -   wherein v is from about 0 to about 97.999 mole percent;    -   wherein f is from about 1 to about 97.999 mole percent;    -   wherein c is from about 1 to about 40 mole percent; and    -   wherein a+v+f+c=100.

ii) using a fluorometer to detect the fluorescent signal of said taggedtreatment polymer;

iii) converting the fluorescent signal of said tagged treatment polymerto the concentration of said tagged treatment polymer; and

iv) adjusting the concentration of said tagged treatment polymeraccording to what the desired concentration is for said tagged treatmentpolymer in said industrial water system.

The fifth aspect of the instant claimed invention is a method formaintaining the desired amount of tagged treatment polymer in anindustrial water system comprising the steps of:

a) adding an inert tracer and a tagged treatment polymer to the water ofan industrial water system, wherein said tagged treatment polymer isselected from the group consisting of:G_(a)Q_(j)W_(t)  (1)

-   -   wherein G is Monomer (Purple), as previously defined;    -   wherein Q is selected from the group consisting of acrylic acid        and salts thereof, methacrylic acid and salts thereof, maleic        acid and salts thereof, maleic anhydride, acrylamide, crotonic        acid, acrylamidomethylpropane sulfonic acid and salts thereof;    -   wherein W is selected from the group consisting of:        acrylic acid and salts thereof, methacrylic acid and salts        thereof, itaconic acid and salts thereof, maleic acid and salts        thereof, maleic anhydride, crotonic acid and salts thereof,        acrylamide, methacrylamide, vinyl sulfonic acid, styrene        sulfonate, N-tertbutylacrylamide, N-isopropylacrylamide,        butoxymethylacrylamide, N,N-dimethylacrylamide,        N,N-diethylacrylamide, dimethylaminoethyl acrylate methyl        chloride quaternary salts, dimethylaminoethyl acrylate benzyl        chloride quaternary salts, dimethylaminoethyl acrylate methyl        sulfate quaternary salt, dimethylaminoethyl methacrylate methyl        sulfate quaternary salt, dimethylaminoethyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl methacrylamide        methyl sulfate quaternary salts, diallyldimethyl ammonium        chloride, N-vinyl formamide, dimethylamino ethyl methacrylate        acid salts (including, but not limited to, sulfuric acid and        hydrochloride acid salts), dimethylaminoethyl methacrylate        methyl chloride quaternary salt, dimethylaminoethyl methacrylate        benzyl chloride quaternary salt, methacrylamidopropyl trimethyl        ammonium chloride, acrylamidopropyl trimethyl ammonium chloride,        methylene bis acrylamide, triallylamine, acid salts of        triallylamine, ethylene glycol dimethacrylate,        hydroxymethylacrylate, hydroxyethylacrylate,        hydroxypropylacrylate, hydroxypropylmethacrylate, diethylene        glycol dimethacrylate, triethylene glycol dimethylacrylate,        polyethylene glycol dimethacrylate, glycidyl methacrylate,        acrylamidomethylpropane sulfonic acid and the sodium salt        thereof, vinyl alcohol, vinyl acetate, and N-vinylpyrrolidone;

with the proviso that Q and W cannot both be the same;

-   -   wherein a is from about 0.001 to about 10.0 mole percent;    -   wherein j is from about 0 to about 99.999 mole percent;    -   wherein t is from about 0 to about 99.999 mole percent; and    -   wherein a+j+t=100;        G_(a)Q_(v)W_(f)S_(c)  (1)    -   wherein G is as previously defined;    -   wherein Q is as previously defined;    -   wherein W is as previously defined, with the proviso that Q and        W cannot both be the same;    -   wherein S is selected from the group consisting of        sulfomethylacrylamide and sulfoethylacrylamide;    -   wherein a is from about 0.001 to about 10.00 mole percent;    -   wherein v is from about 0 to about 97.999 mole percent;    -   wherein f is from about 1 to about 97.999 mole percent;    -   wherein c is from about 1 to about 40 mole percent; and    -   wherein a+v+f+c=100.

such that a desired concentration of said tagged treatment polymer ispresent in said water;

b) using a fluorometer to detect the fluorescent signals of said inerttracer and said tagged treatment polymer;

c) converting the fluorescent signals of said inert tracer and saidtagged treatment polymer to the concentration of said inert tracer andsaid tagged treatment polymer; and

d) adjusting the concentration of said tagged treatment polymeraccording to what the desired concentration is for said tagged treatmentpolymer in said industrial water system.

DETAILED DESCRIPTION OF THE INVENTION

Throughout this patent application the following definitions apply:

“anionic counter ion” refers to an organic or inorganic ion that bears anegative charge to counterbalance the positive charge present on themonomer. Examples include, but are not limited to chloride, sulfate,acetate, methylsulfate, hydroxide and bromide;“aliphatic amine” refers to amines in which the amine group is attachedto a saturated carbon atom;“substituted aliphatic amine” refers to amines in which the amine groupis attached to a saturated carbon of an organic molecule which may bearfunctional groups such as hydroxyl, carboxyl, etc.;“1,2-diamino-substituted aromatic compound” refers to aromatic diaminesin which the two amino groups are attached to two adjacent carbons of anaromatic compound;“diamines” refers to an organic molecule which bears two amino groupsanywhere in the molecule;“Aldrich” refers to Aldrich Chemical Company, P.O. Box 2060, Milwaukee,Wis. 53201 USA, Telephone Numbers (414) 273-3850 and (800) 558-9160;“alkyl”, whenever it is used, refers to a fully saturated hydrocarbonmoiety with from 1 to 10 carbon atoms;“dialkylamino” refers to a moiety of the formula R₂₁—N—R₂₂, where R₂₁and R₂₂ are alkyl;“alkoxy” refers to a moiety of the formula RO—, where R is alkyl;“alkylamidoalkyl” refers to a moiety of the formula R—C(O)NH—R₁—, whereR and R₁ are alkyl;“alkylamino” refers to a moiety of the formula R—NH—, where R is alkyl;“alkoxylalkyl” refers to a moiety of the formula R—O—R₁, where R and R₁are alkyl;“aryl” refers to a moiety of the formula Ar—, where Ar is an aromaticunit; “carboxylate” refers to a moiety of —C(O)OM, where M is H, Na oranother cationic counter ion;“halogen” refers to a moiety selected from the group consisting of F,Cl, Br, and I;“hydroxyalkyl” refers to a moiety where an —OH group is attached to analkyl group;“Nalco” refers to Ondeo Nalco Company, Ondeo Nalco Center, Naperville,Ill. (630) 305-1000;“vinyl” refers to a moiety which has a carbon-carbon double bond;“vinylbenzyl” refers to a moiety of the formula;

and “vinylbenzyloxy” refers to a moiety of the formula:

“Chain Transfer Agent” refers to any molecule, used in free-radicalpolymerization, which will react with a polymer radical forming a deadpolymer and a new radical. Representative Chain Transfer Agents arelisted by K. C. Berger and G. Brandrup, “Transfer Constants to Monomer,Polymer, Catalyst, Solvent, and Additive in Free RadicalPolymerization,” Section II, pp. 81–151, in “Polymer Handbook,” editedby J. Brandrup and E. H. Immergut, 3d edition, 1989, John Wiley & Sons,New York.

“Cross-Linking Agent” refers to an ethylenically unsaturated monomereither containing at least two sites of ethylenic unsaturation orcontaining one site of ethylenic unsaturation and one site of a reactivegroup such as an epoxide or an aldehyde. A Cross-Linking Agent is addedto branch or increase the molecular weight of the tagged treatmentpolymer of this invention. Representative Cross-Linking Agents includeN,N-methylenebisacrylamide, N,N-methylenebismethacrylamide, polyethyleneglycol diacrylate, ethylene glycol dimethacrylate, diethylene glycoldimethacrylate, triethylene glycol dimethacrylate, polyethylene glycoldimethacrylate, polypropylene glycol dimethacrylate, N-vinyl acrylamide,divinyl benzene, triallyl ammonium salts, N-methyl allylacrylamide,glycidyl acrylate, acrolein, methylolacrylamide, glyoxal,epichlorohydrin, and the like. The crosslinker is added at from about0.0001 to about 10, preferably from about 0.0001 to about 0.2 weightpercent based on the weight of the polymer;

“Branching Agent” refers to a “Cross-Linking Agent” that is administeredat a low level (less than 0.05 weight percent based on the weight of thepolymer). It is understood that Branching Agents are added to form“branches” not cross-links; and

“HLB” refers to a hydrophilic-lipophilic balance number.

The present invention is based upon the discovery of a group offluorescent monomers which are useful in the preparation of taggedtreatment polymers containing same, with said tagged treatment polymersin turn being able to provide a means for achieving better monitoring inindustrial water systems.

The first aspect of the instant claimed invention is a fluorescentmonomer selected from the group consisting of compounds of the formulae:

-   -   wherein R₃ is sulfonic acid and its salts or carboxylic acid and        its salts or allyloxy or vinylbenzyloxy; and    -   R₄ is sulfonic acid and its salts or carboxylic acid and its        salts or allyloxy or vinylbenzyloxy; with the proviso that when        one of R₃ or R₄ is sulfonic acid and its salts or carboxylic        acid and its salts, the other must be allyloxy or        vinylbenzyloxy.    -   Preferred monomers are selected from the group consisting of    -   Monomer (Purple),    -   wherein R₃ is sulfonic and carboxylic acid; and    -   R₄ allyloxy and vinylbenzyloxy.

The most preferred monomers are monomers of formula Monomer (Purple)where

-   -   R₃ is carboxylic acid; and    -   R₄ is vinylbenzyloxy and allyloxy.    -   Acceptable names for the most preferred monomers are:    -   5-allyloxy-4′-carboxyl-1,8-naphthoylene-1′,2′ benzimidazole and    -   6-vinylbenzyloxy-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole.

Monomers of formula (Purple) can be synthesized by using two differentsynthetic routes. Materials required for these syntheses arecommercially available and can be obtained from Aldrich.

The first synthetic route involves initially reacting a sulfonic orcarboxylic-substituted naphthalic anhydride with 2,3-diamino-phenol.This compound is then further reacted with an allyl or vinylbenzylhalide to yield Monomer (Purple) where R₃ is allyloxy or vinylbenzyloxyand R₄ is carboxylic or sulfonic acid.

The second synthetic route involves reacting 4-hydroxy-1,8-naphthalicanhydride with a carboxylic or sulfonic-substituted-diamino aromaticcompound. This compound is then further reacted with an allyl orvinylbenzyl halide to yield Monomer (Purple) where R₃ is carboxylic orsulfonic acid and R₄ is allyloxy or vinylbenzyloxy.

“Tagging” the polymer through the use of the fluorescent monomers ofthis invention is achieved by synthesizing the polymer in the presenceof the fluorescent monomer.

Accordingly, once a monomer of Monomer (Purple) is synthesized, theselected monomer can be used to synthesize tagged treatment polymers offormula:G_(a)Q_(j)W_(t)  (1)

-   -   wherein G is Monomer (Purple), as previously defined;    -   wherein Q is selected from the group consisting of acrylic acid        and salts thereof, methacrylic acid and salts thereof, maleic        acid and salts thereof, maleic anhydride, acrylamide, crotonic        acid acrylamidomethylpropane sulfonic acid and salts thereof;    -   wherein W is selected from the group consisting of:        acrylic acid and salts thereof, methacrylic acid and salts        thereof, itaconic acid and salts thereof, maleic acid and salts        thereof, maleic anhydride, crotonic acid and salts thereof,        acrylamide, methacrylamide, vinyl sulfonic acid, styrene        sulfonate, N-tertbutylacrylamide, N-isopropylacrylamide,        butoxymethylacrylamide, N,N-dimethylacrylamide,        N,N-diethylacrylamide, dimethylaminoethyl acrylate methyl        chloride quaternary salts, dimethylaminoethyl acrylate benzyl        chloride quaternary salts, dimethylaminoethyl acrylate methyl        sulfate quaternary salt, dimethylaminoethyl methacrylate methyl        sulfate quaternary salt, dimethylaminoethyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl acrylamide methyl        sulfate quaternary salts, dimethylaminopropyl methacrylamide        methyl sulfate quaternary salts, diallyldimethyl ammonium        chloride, N-vinyl formamide, dimethylamino ethyl methacrylate        acid salts (including, but not limited to, sulfuric acid and        hydrochloride acid salts), dimethylaminoethyl methacrylate        methyl chloride quaternary salt, dimethylaminoethyl methacrylate        benzyl chloride quaternary salt, methacrylamidopropyl trimethyl        ammonium chloride, acrylamidopropyl trimethyl ammonium chloride,        methylene bis acrylamide, triallylamine, acid salts of        triallylamine, ethylene glycol dimethacrylate,        hydroxymethylacrylate, hydroxyethylacrylate,        hydroxypropylacrylate, hydroxypropylmethacrylate, diethylene        glycol dimethacrylate, triethylene glycol dimethylacrylate,        polyethylene glycol dimethacrylate, glycidyl methacrylate,        acrylamidomethylpropane sulfonic acid and the sodium salt        thereof, vinyl alcohol, vinyl acetate, and N-vinylpyrrolidone;

with the proviso that Q and W cannot both be the same;

-   -   wherein a is from about 0.001 to about 10.0 mole percent;    -   wherein j is from about 0 to about 99.999 mole percent;    -   wherein t is from about 0 to about 99.999 mole percent; and    -   wherein a+j+t=100;        G_(a)Q_(v)W_(f)S_(c)  (2)    -   wherein G is as previously defined;    -   wherein Q is as previously defined;    -   wherein W is as previously defined, with the proviso that Q and        W cannot both be the same;    -   wherein S is selected from the group consisting of        sulfomethylacrylamide and sulfoethylacrylamide;    -   wherein a is from about 0.001 to about 10.00 mole percent;    -   wherein v is from about 0 to about 97.999 mole percent;    -   wherein f is from about 1 to about 97.999 mole percent;    -   wherein c is from about 1 to about 40 mole percent; and    -   wherein a+v+f+c=100.

These tagged treatment polymers can be synthesized by following theprocedure for conventional free radical polymerization in an aqueousmedium. They can be made by water-in-oil polymerization methods ordispersion polymerization methods or solution polymerization methods.For those tagged treatment polymers containing a sulfomethylated orsulfoethylated acrylamide, the polymers are first created with anacrylamide moiety, and then the acrylamide groups are sulfomethylatedusing a suitable “sulfo” reagent such as formaldehyde and sodiummetabisulfite.

Procedure for Synthesizing Water-In-Oil Emulsion Polymers

The preparation of high molecular weight water-in-oil emulsion polymershas been described in the following references: U.S. Pat. No. 2,982,749assigned to The Dow Chemical Company; U.S. Pat. No. 3,284,393 assignedto The Dow Chemical Company; U.S. Pat. No. 3,734,873 assigned to NalcoChemical Company; “Mechanism, Kinetics and Modeling of theInverse-Microsuspension Homopolymerization of Acrylamide,” by Hundeler,D., Hamielec, A. and Baade, W., Polymer (1989), 30(1), 127–42; and“Mechanism, Kinetics and Modeling of Inverse-MicrosuspensionPolymerization: 2. Copolymerization of Acrylamide with QuaternaryAmmonium Cationic Monomers,” by D. Hunkeler and A. E. Hamielec; Polymer(1991), 32(14), 2626–40.

A general procedure for the manufacture of water-in-oil emulsion taggedtreatment polymers is provided to illustrate the preparation of thesetagged treatment polymers using fluorescent monomers. The types andquantities of specific components in the formula (monomers, initiators,Chain Transfer Agents, for example) will vary depending upon the type ofpolymer (cationic, anionic, nonionic) that is being synthesized.

An aqueous phase is prepared by mixing together in water one or morewater soluble monomers, and different polymerization additives such asinorganic salts, chelants, pH buffers, Chain Transfer Agents andBranching or Cross-Linking Agents. In order to synthesize the taggedtreatment polymers of the instant claimed invention, a monomer offormula Monomer (Purple) is included in the aqueous phase at the desiredlevel.

An organic phase is prepared by mixing together an inert hydrocarbonliquid with one or more oil soluble surfactants. The surfactant mixtureshould have a low HLB, to ensure the formation of an oil continuousemulsion. Appropriate surfactants for water-in-oil emulsionpolymerizations, which are commercially available, are compiled in theNorth American Edition of McCutcheon's Emulsifiers & Detergents. The oilphase may need to be heated to ensure the formation of a homogeneous oilsolution.

The oil phase is charged into a reactor equipped with a mixer, athermocouple, a nitrogen purge tube, and a condenser. Adding the aqueousphase to the reactor containing the oil phase with vigorous stirringforms an emulsion. The resulting emulsion is heated to the desiredtemperature, purged with nitrogen, and a free-radical initiator isadded. The reaction mixture is stirred for several hours under anitrogen atmosphere at the desired temperature. Upon completion of thereaction, the water-in-oil emulsion polymer is cooled to roomtemperature, where any desired post-polymerization additives, such asantioxidants, or a high HLB surfactant (as described in U.S. Pat. No.3,734,873) may be added.

The resulting emulsion polymer is a free-flowing liquid. An aqueoussolution of the water-in-oil emulsion polymer can be generated by addinga desired amount of the emulsion polymer to water with vigorous mixingin the presence of a high-HLB surfactant (as described in U.S. Pat. No.3,734,873).

Procedure for Synthesizing Dispersion Polymers

The preparation of dispersion polymers has been described in thefollowing references: U.S. Pat. No. 4,929,655, assigned to HymoCorporation; U.S. Pat. No. 5,006,590, assigned to Hymo Corporation; U.S.Pat. No. 5,597,859, assigned to Nalco Chemical Company; European Patent657,478; U.S. Pat. No. 5,597,858, assigned to Nalco Chemical Company andEuropean Patent 630,909.

A general procedure for the manufacture of dispersion tagged treatmentpolymers is provided in the following text in order to illustrate thepreparation of dispersion tagged treatment polymers comprising thefluorescent monomers described herein. The types and quantities ofspecific components in the formula (salts and stabilizer polymers, forexample) will vary depending upon the type of polymer (cationic,anionic, nonionic) that is being synthesized.

An aqueous solution containing one or more inorganic salts, one or morewater-soluble monomers, any polymerization additives such as chelants,pH buffers, Chain Transfer Agents, Branching or Cross-Linking Agents anda water-soluble stabilizer polymer is charged to a reactor equipped witha mixer, a thermocouple, a nitrogen purging tube, and a water condenser.The monomer solution is mixed vigorously, heated to the desiredtemperature, and then a water-soluble initiator is added. The solutionis purged with nitrogen while maintaining temperature and mixing forseveral hours. After this time, the products are cooled to roomtemperature, and any post-polymerization additives are charged to thereactor. Water continuous dispersions of water-soluble polymers are freeflowing liquids with product viscosities generally 100–10,000 cP,measured at low shear. Thus, in order to prepare tagged polymers asdispersions, a monomer of formula Monomer (Purple) is included in thereaction mixture at the desired level.

Procedure for Synthesizing Solution Polymers

A general procedure for the manufacture of solution polymers is providedto illustrate the preparation of the solution tagged treatment polymerscomprising the fluorescent monomers described herein. One typicalprocess is described as follows: One or more monomers are added to avessel followed by neutralization with a suitable base. The fluorescentmonomer can then be added to this monomer solution after neutralizationor alternatively, to the reaction vessel. A determined amount of wateris then added to the reaction vessel, which is then heated and purged.Polymerization catalysts may also be added to the vessel initially orfed in gradually during the course of the reaction. Water solublepolymerization initiators such as any azo or redox initiator orcombination thereof are added along with the monomer solution to thereaction mixture in separate feeds over the same amount of time, usually2 to 6 hours. The reaction temperature is maintained at about 60–70° C.Additional initiator may be used after addition is complete to reduceresidual monomer levels.

The amount of fluorescent monomer that is used should be an amountsufficient to allow the tagged treatment polymer to be detected in theaqueous environment that it is used. The minimum amount of fluorescentmoiety that can be used is that amount which gives a signal-to-noiseratio (S/N) of 3 at the desired tagged treatment polymer dosage. Thesignal-to-noise ratio is that value where the magnitude of thetransduced signal (including but not limited to electronic and opticalsignals) due to the presence of a target analytic in a measurementdevice is greater than or equal to a level three (3) times the magnitudeof a transduced signal where the analyte (species) of interest is notpresent in the measurement device.

The amount of fluorescent monomer in the tagged treatment polymers is inthe range of from about 0.001 mole percent to about 10 mole percent,preferably from about 0.01 mole percent to about 0.4 mole percent, andmost preferably from about 0.05 mole percent to about 0.35 mole percent.For purposes of this patent application, mole percent of all monomers inthe tagged treatment polymer is calculated based on weight percent. Forpurposes of this patent application, the subscripts a, j, t, v, f and crefer to the mole percent of each monomer component of the taggedtreatment polymers.

The remainder of the tagged treatment polymer can have one, two or threeadditional monomers in it.

All molecular weights in this patent application are weight averagemolecular weights measured by gel permeation chromatography (GPC)calculated from both refractive index and fluorescent detector tracesusing polystyrene sulfonate (PSS) molecular weight standards. Taggedtreatment polymers that have a wide range of molecular weights can beprepared by using the procedures described previously by those skilledin the art.

The molecular weights of the instant claimed tagged treatment polymersare from about 500 atomic mass units (hereinafter “a.m.u.”) to about10,000,000 a.m.u. Preferably the molecular weights are from about 2000a.m.u. to about 500,000 a.m.u. Most preferably, the molecular weightsare from about 5000 a.m.u. to about 40,000 a.m.u.

Preferred tagged polymers are made via solution polymerizationtechniques and have a molecular weight from about 5,000 a.m.u. to about40,000 a.m.u.

Preferred tagged treatment polymers are where said fluorescent monomeris selected from the group consisting of:

5-allyloxy-4′-carboxy-1,8 naphthoylene-1′,2′-benzimidazole (5ACNB) and6-vinylbenzyloxy-4′-carboxyl-1,8-naphthoylene-1′,2′-benzimidazole(6-VBCNB).

The more preferred polymers are where G is Monomer (Purple) aspreviously defined; Q, if present in the polymer, is selected from thegroup consisting of acrylamide and acrylic acid;

W, if present in the polymer, is selected from the group consisting ofacrylamide and acrylamidomethylpropane sulfonic acid; and

S, if present in the polymer, is N-sulfomethylacrylamide.

The most preferred polymers are selected from the group consisting of

0.04 mole % 5-ACNB, 49.98 mole % acrylic acid, 49.98 mole % acrylamide;and

0.04 mole % 6-VBCNB, 49.98 mole % acrylic acid, 49.98 mole % acrylamide.

Once created the tagged treatment polymers of the instant claimedinvention can be used as scale inhibitors in industrial water systems.As these polymers are consumed performing that function, theirfluorescent signal will decrease and thus the decrease in thefluorescent signal can be used to indicate that undesired scaling istaking place.

The tagged treatment polymers containing a fluorescent monomer can beused in industrial water systems. Examples of industrial water systemsare cooling tower water systems (including open recirculating, closedand once-through systems); petroleum wells, downhole formations,geothermal wells and other oil field applications; boilers and boilerwater systems; mineral process waters including mineral washing,flotation and benefaction; paper mill digesters, paper production,washers, bleach plants and white water systems; black liquor evaporatorsin the pulp industry; gas scrubbers and air washers; continuous castingprocesses in the metallurgical industry; air conditioning andrefrigeration systems; industrial and petroleum process water; indirectcontact cooling and heating water, such as pasteurization water; waterreclamation and purification systems; membrane filtration water systems;food processing streams (meat, vegetable, sugar beets, sugar cane,grain, poultry, fruit and soybean); and waste treatment systems as wellas in clarifiers, liquid-solid applications, municipal sewage treatmentand industrial or municipal water systems.

The tagged treatment polymer comprising a fluorescent monomer may beused in the industrial water systems singly or in combination with otherpolymers, which are not tagged. The dosage rate of tagged treatmentpolymer in an industrial water system, when it is being used as a scaleinhibitor, is from about 1 to about 100 milligrams of solid componentactive per liter of water.

The third aspect of the instant claimed invention is a process for theinhibition of scale formation in an industrial water system whichcomprises introducing into said industrial water system a taggedtreatment polymer, previously described, in an amount sufficient toinhibit scale formation. The amount of the tagged treatment polymercomprising the fluorescent monomer added to an industrial water systemis in the range of about 1.0 milligrams (mg) to about 30 milligrams ofthe total solid polymer actives per liter of water in the system. Thisis equivalent to about 1 part per million (ppm) to about 30 ppm.

When used in an industrial water system, the fluorescent signal of thetagged treatment polymers can be used to determine how much taggedtreatment polymer is present in the industrial water system. Therefore,the fourth aspect of the instant claimed invention is:

A method for maintaining the desired amount of tagged treatment polymerin an industrial water system comprising the steps of:

-   -   i) adding to said industrial water system a tagged treatment        polymer, wherein said tagged treatment polymer is as previously        described;    -   ii) using a fluorometer to detect the fluorescent signal of said        tagged treatment polymer;    -   iii) converting the fluorescent signal of said tagged treatment        polymer to the concentration of said tagged treatment polymer;        and    -   iv) adjusting the concentration of said tagged treatment polymer        according to what the desired concentration is for said tagged        treatment polymer in said industrial water system.    -   The fifth aspect of the instant claimed invention is as follows.

A method for maintaining the desired amount of tagged treatment polymerin an industrial water system comprising the steps of:

-   -   a) adding an inert tracer and a tagged treatment polymer, as        previously described, to water such that a desired concentration        of said tagged treatment polymer is present in said water;    -   b) using a fluorometer to detect the fluorescent signals of said        inert tracer and said tagged treatment polymer;    -   c) converting the fluorescent signals of said inert tracer and        said tagged treatment polymer to the concentration of said inert        tracer and said tagged treatment polymer; and    -   d) adjusting the concentration of said tagged treatment polymer        according to what the desired concentration is for said tagged        treatment polymer in the industrial water system.

An advantage of the fluorescent monomers of this invention is that intheir use in the formation of a tagged treatment polymer, thefluorescent monomer is not significantly affected by other structures inthe polymer or by other ingredients in the system. Thus, the polymersare stable in the presence of STA.BR.EX®, where STA.BR,EX® is thetrademark for an oxidizing biocide, available from Nalco ChemicalCompany, One Nalco Center, Naperville, Ill. 60563.

A further advantage of the tagged treatment polymers of this inventionis that the spectral properties, i.e. both excitation and emission ofthe polymers are in the near visible wavelength region (>370 nm), thusallowing the use of solid state instrumentation and potentially minimizeinterferences that generally occur in the UV wavelength region.

The following examples are presented to be illustrative of the presentinvention and to teach one of ordinary skill how to make and use theinvention. These examples are not intended to limit the invention or itsprotection in any way.

EXAMPLES Monomer Example 1

Preparation of5-allyloxy-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole (5-ACNB)

Step One: Synthesis of5-chloro-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole(I)

A 100 ml round bottom flask was charged with 4-chloro-1,8-naphthalicanhydride (4.65 g, 19.99 mmol) 3,4-diaminobenzoic acid (3.08 g, 20.24mmol), and glacial acetic acid (50 ml). The mixture was refluxed undernitrogen for 5 hours and cooled. The solid was collected, washed withisopropanol, and dried under vacuum.

Step Two: Synthesis of5-allyloxy-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole

A 300 ml Parr reactor was charged with5-chloro-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole(I) (0.7 g, 2.01mmol), allyl alcohol (20 ml, 0.294 mole), and potassium hydroxide (0.23g, 4.1 mmol). The reactor was purged for 10 minutes, sealed and thenheated to 150° C. for 4 hours. Upon cooling, the volatiles were strippedand a crude orange solid was obtained.

Monomer Example 2

Preparation 6-vinylbenzyloxy-4′-carboxy-1,8-naphthoylene1′,2′-benzimidazole (6-VBCNB)

Step One: Synthesis of6-hydroxy-4′-carboxyl-1,8-naphthoylene-1′,2′-benzimidazole(I)

A 100 ml round bottom flask was charged with 3-hydroxy-1,8-naphthalicanhydride (4.29 g, 20.04 mmol), 3,4-diaminobenzoic acid (3.04 g, 19.97mmol), and glacial acetic acid (50 ml). The mixture was refluxed undernitrogen for 5 hours and cooled. The solid was collected, washed withisopropanol, and dried under vacuum.

Step Two: Synthesis of6-vinylbenzyloxy-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole

A 100 ml round bottom flask was charged with6-hydroxy-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole(I) (1.66 g,4.5 mmol), vinyl benzyl chloride (0.92 g, 6.05 mmol), and potassiumcarbonate (2.38 g, 10 mmol). The mixture was refluxed in acetone for 8hours and cooled. The mixture was then poured into water, acidified, andthe orange solid was collected.

Polymer Example 1 Preparation of 0.04 mole % 5-ACNB/49.98 mole % AcrylicAcid/49.98 mole % Acrylamide

A reactor was charged with deionized water (125 g), and 5-ACNB (preparedaccording to Monomer Example 1, 0.474 g, 1.16 mmol) and heated to 65° C.with stirring (750 rpm). At temperature, initiator solution 1 (3.50 gammonium persulfate in 19.59 g of deionized water), and initiatorsolution 2 (10.48 g sodium metabisulfite in 30.30 g of deionized water)were added separately at a constant flow rate over a period of 3.25hours. Five minutes after initiator feed had started, a monomer solutionconsisting of deionized water (13.57 g), acrylic acid (95.43 g, 1.33mole), 48.7% acrylamide (193.23 g, 1.33 mole), and 50% sodium hydroxide(42.3 g, 0.529 mole) was added separately at a constant flow rate over aperiod of 3 hours. After monomer and initiator feeding was complete, thereaction was held at temperature for an additional 30 minutes. Theproduct had a molecular weight of approximately 11,600 and 92%incorporation of the tag, as measured by gel permeation chromatography(GPC) calculated from both refractive index and fluorescent detectortraces using polystyrene sulfonate (PSS) MW standards.

Polymer Example 2 Preparation of 0.04 mole % 6-VBCNB/49.98 mole %Acrylic Acid/49.98 mole % Acrylamide

A 5-neck, 1000 ml resin flask equipped with a mechanical stirrer, sidebaffles, reflux condenser, and nitrogen purge was charged with deionizedwater (133.96 g) and heated to 65° C. with stirring (800 rpm). Attemperature, initiator solution 1 (2.56 g ammonium persulfate in 30 g ofdeionized water), initiator solution 2 (7.74 g sodium metabisulfite in30g of deionized water), and a monomer solution consisting of acrylicacid (88.12 g, 1.22 mole), 49.6% acrylamide (177.56 g, 1.22 mole), 50%sodium hydroxide (36.4 g, 0.455 mole), and 6-VBCNB (prepared accordingto Monomer Example 2, 0.42 g, 0.943 mmol) were added separately at aconstant flow rate over a period of 2 hours. After monomer and initiatorfeeding was complete, the reaction was held at temperature for anadditional 1 hour. The product had a molecular weight of approximately15,000 and 98% incorporation of the tag, as measured by gel permeationchromatography (GPC) calculated from both refractive index andfluorescent detector traces using polystyrene sulfonate (PSS) MWstandards.

Method of Use Example 1

Stability and Performance Testing

The fluorescence properties (excitation and emission maxima) of polymersprepared using the monomers are given in Table I. Excitation maxima areall greater than 370 nm. The fluorescence of the polymers remainedinvariant over a pH range of approximately 2–12.

Another important feature of these polymers is the stability of thefluorescence in the presence of oxidizing biocides. The oxidizingbiocide stability test was performed in the following manner. Solutionsof simulated water were prepared with the desired levels of cations andanions at the desired pH. For these experiments the simulated coolingwater contained 360 ppm Ca (as CaCO₃), 200 ppm Mg (as CaCO₃), 300 ppmalkalinity (as CaCO₃) and 15 ppm of a stable phosphonate, to stabilizethe water and prevent CaCO₃ precipitation. The water was then adjustedto the desired pH with HCl or NaOH. Tests were performed at pH 7 and 9.A series of three amber bottles were labeled with the desired testsample. A 25 ml aliquot of the simulated water was delivered into eachof the three labeled bottles. To one of the bottles (labeled “B”) wasdelivered 30 μl of a 1200 ppm stock solution of bleach. To a secondbottle (labeled “S”) was delivered 30 μl of a 1200 ppm stock solution ofSTABREX® biocide, available from Nalco. To the third bottle (labeled“N”) was delivered 30 μl distilled water. The amount of free and totalchorine was measured immediately after the samples were prepared and 24hrs later at the time of fluorescence analysis. The bottles were storedfor 24 hrs in the dark. After 24 hours, fluorescence measurements weredone using the sample marked “N” as the reference sample. The %fluorescence consumed (hereinafter “% Fl consumed”) in the presence ofan oxidizing biocide was calculated as shown below. It is important tonote that lower levels of % Fl Consumed indicate lower loss offluorescent emission. Results for polymers containing the fluorescentmonomers are given in Table I.

${\%\mspace{14mu}{F1}\mspace{14mu}{Consumed}} = {\frac{{{Intensity}\mspace{14mu}{of}\mspace{14mu} N\mspace{14mu}{Sample}} - {{Intensity}\mspace{14mu}{of}\mspace{14mu} B\mspace{14mu}{or}\mspace{14mu} S\mspace{14mu}{Sample}}}{{Intensity}\mspace{14mu}{of}\mspace{14mu} N\mspace{14mu}{Sample}} \times 100}$

TABLE I Summary of Fluorescence Properties and Oxidizing BiocideStability of a Polymer Polymer Monomer Fluorescence Oxidizing BiocideStability Example Name Properties (% Fluorescence Consumed) 1 5-ACNB  Ex= 396 nm STABREX (pH9) = 1% Em = 511 nm

When using the tagged treatment polymer as a compound of ascale-inhibitor product in an industrial water system, the only decreaseor loss of fluorescence signal from the polymer should be due to loss ofthe polymer under scaling conditions. When identifying a scaling eventas the reason for a loss of fluorescence, it is undesirable for thelevel of fluorescence to also vary based on pH changes, other componentspresent in the cooling water system, or from oxidizing biocides such asthe STABREX® biocide system.

If the amount consumed by an oxidizing biocide is equal to or less than10% of the signal, then the tagged treatment polymer can be used in anindustrial water system. Although a small amount of the tagged treatmentpolymer is consumed in the presence of 1 ppm STABREX® biocide, theresults given above indicate that the tagged treatment polymers aresufficiently stable to be used in industrial water systems whereSTABREX® is present.

The specific examples herein disclosed are to be considered as beingprimarily illustrative. Various changes beyond those described will, nodoubt, occur to those skilled in the art; such changes are to beunderstood as forming a part of this invention insofar as they fallwithin the spirit and scope of the appended claims.

1. A fluorescent monomer selected from the group consisting of compoundsof the formulae:

wherein R₃ is sulfonic acid and its salts or carboxylic acid and itssalts or allyloxy or vinylbenzyloxy; and R₄ is sulfonic acid and itssalts or carboxylic acid and its salts or allyloxy or vinylbenzyloxy;with the proviso that when one of R₃ or R₄ is sulfonic acid and itssalts or carboxylic acid and its salts, the other must be allyloxy orvinylbenzyloxy.
 2. A fluorescent monomer of claim 1, which is Monomer(Purple), wherein said monomer is named:5-allyloxy-4′-carboxyl-1,8-naphthoylene-1′,2′ benzimidazole.
 3. Afluorescent monomer of claim 1 which is6-vinylbenzyloxy-4′-carboxy-1,8-naphthoylene-1′,2′-benzimidazole.